Self-assembling peptides can be used to design new materials for medical and biological applications. Here we synthesized and characterized two novel cyclic γ-peptides (γ-CPs) with hydrophobic inner surfaces. The NMR and FT-IR studies confirmed that the CPs could self-assemble into parallel stacking structures via intermolecular H-bonds and π-π interactions. The morphologies of the self-assembly CPs showed bundles of nanotubes via transmission electron microscopy (TEM); these nanotubes form water channels to transport water across the lipid membrane. The properties of blocking the transport of protons like natural water channels showed that the hydrophobic inner surfaces are important in artificial transmembrane water channel designs. These studies also showed that water transport was a function of pore size and length of the assemblies.
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http://dx.doi.org/10.3389/fchem.2020.00368 | DOI Listing |
EMBO Rep
January 2025
Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, China.
Cyclic diguanosine monophosphate (c-di-GMP) is a ubiquitous bacterial secondary messenger with diverse functions. A previous Escherichia coli proteome microarray identified that c-di-GMP binds to the 23S rRNA methyltransferases RlmI and RlmE. Here we show that c-di-GMP inhibits RlmI activity in rRNA methylation assays, and that it modulates ribosome assembly in the presence of kanamycin.
View Article and Find Full Text PDFJ Pathol Clin Res
January 2025
State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and National Clinical Research Center for Digestive Diseases, Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, PR China.
CXC chemokine receptor 4 (CXCR4) and programmed cell death-ligand 1 (PD-L1) are two critical molecules involved in the tumor immune microenvironment. However, the impact of platinum drugs, such as cisplatin, on CXCR4 or PD-L1 expression and the underlying mechanisms in gastric cancer (GC) remain unknown. Moreover, the correlation between their expression levels in GC remains elusive.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada.
Tambjamines are complex bipyrrole-containing natural products that possess promising bioactive properties. Although is known to produce both cyclic tambjamine MYP1 and the linear precursor (YP1), the biosynthetic machinery used to catalyze the site-selective oxidative carbocyclization at the unactivated 1° carbon of YP1 has remained unclear. Here, we demonstrate that a three-component Rieske system consisting of an oxygenase (TamC) and two redox partner proteins is responsible for this unprecedented activity on YP1 and potentially, a non-native substrate (BE-18591).
View Article and Find Full Text PDFActa Biomater
January 2025
Hengyang Medical School, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, School of Pharmaceutical Science, MOE Key Lab of Rare Pediatric Disease, University of South China, Hengyang 421001, China. Electronic address:
Immune checkpoint blockers (ICBs)-based immunotherapy is a favorable approach for efficient triple-negative breast cancer (TNBC) treatment. However, the therapeutic efficacy of ICBs is greatly compromised by immunosuppressive tumor microenvironments (TMEs) and low expression levels of programmed cell death ligand-1 (PD-L1). Herein, we constructed an amphiphilic prodrug by linking a hydrophobic STING agonist, MSA-2 and a hydrophilic chemotherapeutic drug, gemcitabine (GEM) via an ester bond, which can self-assemble into GEM-MSA-2 (G-M) nanoparticles (NPs) with a tumor growth inhibition (TGI) value of 87.
View Article and Find Full Text PDFActa Biomater
January 2025
College of Basic Medical Sciences, Chongqing Medical University, Chongqing 400016, China. Electronic address:
Cuproptosis is a newly discovered mode of cell death, which is caused by excess copper and results in cell death via the mitochondrial pathway. However, the complex tumor microenvironment (TME) is characterized by many factors, including high levels of glutathione and lack O, limit the application of traditional cuproptosis agents in antitumor therapy. Herein, we report a hyaluronic acid modified copper-manganese composite nanomedicine (CMCNs@HA) to remodel the TME and facilitate efficient cuproptosis in tumor.
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